1. Field of the Invention
The present invention relates generally to nanotechnology and, more particularly, the development and use of artificial (prosthetic) ligaments or tendons comprising nanofibers.
2. Description of Related Art
Ligaments and tendons are bands or sheets of fibrous connective tissue that provide support and stability to the musculoskeletal system. Ligaments extend between adjacent bone structures and serve a primary function of providing appropriate stability to the bone structures to maintain them in an aligned, spaced relation, particularly when subjected to loads in tension or upon torsional movement. Tendons, also capable of withstanding tension, are tough bands of fibrous connective tissue that usually connect muscle to bone.
Over 800,000 injuries to ligaments, tendons and the joint capsule occur every year in the U.S. (Doroski et al., 2007). Among the most common injuries are to the patellar tendon, the anterior cruciate ligament, the posterior cruciate ligament, the medial collateral ligament, the Achilles tendon, the anterior talofibular ligament, the calcaneofibular, the rotator cuff tendons, the acromioclavicular ligament and the gluteus medius tendon (Doroski et al., 2007). Unfortunately, insufficient vascularization impedes complete healing after extreme tearing or rupture of these tissues (Doroski et al., 2007; Freeman et al., 2007; West and Harner, 2005). Therefore, surgical intervention is commonly required to perform autografts, allografts or to treat the injury with prosthetic ligaments or tendons (Freeman et al., 2007; West and Harner, 2005; Jeon et al., 2007; Fujii et al., 1997; Fujishiro et al., 2003; Ciccone et al., 2006; Noyes et al., 1984).
The use of autografts often imparts additional injury to the patient, causing donor site morbidity and increased recovery times, while allograft availability is limited and possesses the risk of transmitting infections and obtaining adverse immunological reactions from the patient (Freeman et al., 2007; West and Harner, 2005). In contrast, artificial ligaments and tendons used in reconstructive surgery do not present these problems but frequently fail over time (Amis and Kempson, 1999; Jadeja et al., 2007). As a consequence, there is a need to develop materials that will allow regeneration or replacement of ligaments and tendons. Such a challenging task should result in biocompatible materials with mechanical properties that will resemble the natural tissues.